Multi-package conversion kit for a pick and place handler

ABSTRACT

The present invention provides a kit and method for package-to-package conversion of a pick and place handler. An input arm assembly is provided with interchangeable vacuum leads such that package-to-package conversion only requires replacing the vacuum lead with a different size vacuum lead. An input/output shuttle plate is provided comprising a block and base plate. The block has a plurality of pocket groupings and a two or more alignment hole groupings. The base plate has two or more alignment pins. Package-to-package conversion is achieved by changing which alignment hole in each alignment hole grouping is set on the alignment pins, thereby selecting the pocket in each pocket grouping corresponding to the alignment hole used. A soak plate is provided having an array of pocket groupings, wherein each pocket grouping has the same pattern of different size/shape pockets to accommodate different packages. Package-to-package conversion is accomplished by programming an offset to the desired pocket in each pocket grouping. An test arm assembly is provided with interchangeable vacuum leads and interchangeable nest pieces such that package-to-package conversion only requires replacing the vacuum lead and nest piece with a different size vacuum lead and nest piece.

BACKGROUND OF INVENTION

[0001] 1) Field of the Invention

[0002] This invention relates generally to surface mount assembly ofsemiconductor devices and more particularly to a method and device forconverting a pick and place handler for use with devices havingdifferent packages and/or different sizes.

[0003] 2) Description of the Prior Art

[0004] Pick and place handlers are widely used in surface mounttechnology for physically moving semiconductor devices during assemblyand test. A vacuum lead is typically used to pick up a semiconductordevice and hold it during transport to a new location (e.g. a circuitboard or a holding fixture). However, different packages and evendifferent sizes of a common package can require different vacuum leads.

[0005] The importance of overcoming the various deficiencies noted aboveis evidenced by the extensive technological development directed to thesubject, as documented by the relevant patent and technical literature.The closest and apparently more relevant technical developments in thepatent literature can be gleaned by considering the following patents.U.S. Pat. No. 5,184,068 (Twigg et al.) describes a pick and placehandler. U.S. Pat. No. 5,966,940 (Gower et al.) shows a thermalconditioning unit that can be incorporated into a pick and placehandler.

SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to provide a method anddevice for converting a pick and place handler to accommodate varioussemiconductor packages and/or sizes.

[0007] It is another object of the present invention to provide aneconomical method and device for converting a pick and place handler toaccommodate various semiconductor packages and/or sizes.

[0008] It is yet another object of the present invention to provide amethod for converting a pick and place handler to accommodate varioussemiconductor packages and/or sizes with reduced conversion and set-uptime.

[0009] To accomplish the above objectives, the present inventionprovides a method and conversion kit which can be used to convert a pickand place handler for a different semiconductor package economically,and with minimum conversion and set-up time. An input arm assembly isprovided with interchangeable vacuum leads such that package-to-packageconversion only requires replacing the vacuum lead with a different sizevacuum lead. An input/output shuttle plate is provided comprising ablock and base plate. The block has a plurality of pocket groupings anda two or more alignment hole groupings. The base plate has two or morealignment pins. Package-to-package conversion is achieved by changingwhich alignment hole in each alignment hole grouping is set on thealignment pins, thereby selecting the pocket in each pocket groupingcorresponding to the alignment hole used. A soak plate is providedhaving an array of pocket groupings, wherein each pocket grouping hasthe same pattern of different size/shape pockets to accommodatedifferent packages. Package-to-package conversion is accomplished byprogramming an offset to the desired pocket in each pocket grouping. Antest arm assembly is provided with interchangeable vacuum leads andinterchangeable nest pieces such that package-to-package conversion onlyrequires replacing the vacuum lead and nest piece with a different sizevacuum lead and nest piece.

[0010] The present invention provides considerable improvement over theprior art. Setup time is reduced because the input arm assembly and testarm assembly can be converted by changing the interchangeable vacuumlead and the interchangeable nest piece as required, instead of changingthe entire input arm assembly and the entire test arm. Set-up time isalso reduced by the soak plate and input/output shuttle plate which canaccommodate different packages, eliminating the need to replace them.Tool inventory and maintenance cost is reduced because separate inputarm assemblies, test arm assemblies, soak plates, and input/outputshuttle plates do not need to be provided and maintained for eachpackage that the pick and place handler is to be used with.

[0011] The present invention achieves these benefits in the context ofknown process technology. However, a further understanding of the natureand advantages of the present invention may be realized by reference tothe latter portions of the specification and attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The features and advantages of a semiconductor device accordingto the present invention and further details of a process of fabricatingsuch a semiconductor device in accordance with the present inventionwill be more clearly understood from the following description taken inconjunction with the accompanying drawings in which like referencenumerals designate similar or corresponding elements, regions andportions and in which:

[0013]FIG. 1 illustrates an input arm according to the prior art;

[0014]FIG. 2 illustrates a soak buffer according to the prior art;

[0015]FIG. 3 illustrates an input/output holding fixture according tothe prior art;

[0016]FIG. 4 illustrates a test arm according to the prior art;

[0017]FIG. 5 illustrates an input arm assembly according to theinvention;

[0018]FIG. 6 illustrates a soak buffer according to the invention;

[0019]FIG. 7 illustrates an input/output shuttle plate according to theinvention;

[0020]FIG. 8 illustrates a block for holding semiconductor devices priorto and after handling by an input arm of a pick and place handler, thatmounts on the shuttle plate shown in FIG. 7, according to the invention;and

[0021]FIG. 9 illustrates a test arm assembly according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described in detail with referenceto the accompanying drawings. The present invention provides a methodand device for converting a pick and place handler for a semiconductordevice with a different package and/or size.

[0023] Problem Identified by the Inventors—FIGS. 1-4

[0024] An input arm (1) known by the inventors to have a problem isshown in FIG. 1. The input arm comprises a vacuum lead (2) which isplaced proximate a semiconductor device to be transported. The vacuumpressure from the vacuum lead lifts the device (picks), and transportsthe device to the desired location, whereupon the vacuum pressure isshut off and the device is released (place). The input arm is typicallyattached to a base handler by clips (3). Different packages, such asball grip array (BGA), quad flat package (QFP), chip scale package(CSP), and plastic lead chip carrier (PLCC), and different package sizescan require different vacuum leads to adequately lift and hold thepackage. Conversion to a different vacuum lead requires changing theinput arm. Maintaining a different input arm for each package/size isexpensive, and the conversion time can increase overall manufacturingcycle time.

[0025] Another problem with converting a pick and place handler to adifferent package/size semiconductor device is that holding fixtures(e.g. soak buffers and I/O shuttle plates, shown in FIGS. 2 and 3respectively) must be changed to accommodate the new package/size.Again, maintaining different fixtures for each package/size isexpensive. Also, the conversion process adversely effects manufacturingcycle time.

[0026] Yet another problem with converting a pick and place handler to adifferent package/size semiconductor device is that a new test armassembly, as shown in FIG. 4, is required. The test arm assemblytypically comprises a contact area, which contacts the electrical leadsof a device to be tested. Maintaining test arms for each package/size isexpensive. The conversion process adversely effects manufacturing cycletime.

[0027] The problem with the prior art conversion kits for pick and placehandlers is that they require an expensive collection of assembly arm,fixtures and test arms. Also, set-up times for converting thereplacement input arm, fixtures, and test arm adversely effectmanufacturing cycle time.

[0028] Preferred Embodiment of the Invention—FIGS. 5-9

[0029] Referring to FIG. 5, the preferred embodiment of the presentinvention begins by providing an input arm assembly (100). The input armassembly comprises a pressure fitting (110), an input arm body (120),input arm clips (130), and a vacuum lead (140) selected from a set ofinterchangeable vacuum leads having different sizes. The correct sizevacuum lead (140) for the semiconductor device to be picked and placed,is inserted in a through hole (150) in the input arm body (120). Thevacuum lead (140) is retained by a set screw on the pressure fitting(110).

[0030] Each vacuum lead (140) has an upper hollow cylindrical portionand a lower hollow cylindrical portion with a flange therebetween. Theupper cylindrical portion is inserted into the through hole (150) in theinput arm body (120). The lower cylindrical portion is moved proximateto a semiconductor device, such that vacuum pressure drawn through thevacuum lead lifts and holds the semiconductor device. A compressionspring (160) is placed over the upper cylindrical portion of the vacuumlead (140) to provide suspension to the input arm assembly. When thevacuum lead contacts a semiconductor device, the spring is compressedand the force on the semiconductor device is reduced.

[0031] A key advantage of the present invention is that the input armcan be converted to a different size vacuum lead by changing to adifferent vacuum lead from the set of interchangeable vacuum leads. Thisreduces set-up time compared to the prior art which requires changingthe entire input arm. Inventory cost is reduced because the presentinvention only requires multiple vacuum leads rather than multiple inputarms. Also, the present invention provides suspension, due to thespring, preventing damage to semiconductor devices when the vacuum leadcontacts those semiconductor devices. Referring to FIG. 6, the soakbuffer (200) of the present invention has an array of pockets groupings(210), wherein each grouping comprises the same pattern of pockets ofdifferent shapes and/or sizes to accommodate different semiconductordevices or packages. During package-to-package conversion, the basehandler of a pick and place handler can be programmed to place packagesinto the corresponding pockets by programming an offset equal to thedistance from the previous pocket in the pocket grouping to the desiredpocket in the pocket grouping. Since only one soak buffer is required,the present invention eliminates the set-up time required to change soakbuffers for different semiconductor packages and eliminates the costassociated with maintaining multiple soak buffers.

[0032] Referring to FIG. 7, the input/output (i/o) shuttle plate of thepresent invention comprises a base plate 310 that can be fastened ontothe base handler of a pick and place handler. For example, the baseplate can be fastened using push locks (360). The base plate comprises 2or more alignment pins (320), most preferably 2. The base plate furthercomprises a series of attachment means groupings (380), such as threadedholes for attaching a block (330 in FIG. 8) to the base plate (310).

[0033] Referring to FIG. 8, the block (330) comprises a series of pocketgroupings (340). Each pocket grouping comprises pockets of differentshapes and/or sizes to accommodate different semiconductor devices orpackages. For example, the pocket grouping could comprise a first pocket(341), a second pocket (342) and a third pocket (343), as shown in FIG.8. However it should be understood that each pocket grouping couldcomprise a greater or lesser number of pockets. The second pocket ineach grouping of pockets is offset from the first pocket by a firstoffset having a first distance and direction. The third pocket of eachgrouping of pockets is offset from the first pocket by a second offsethaving a second distance and direction.

[0034] The block (330) further comprises a series of alignment holegroupings (350), where the number of groupings is equal to the number ofalignment pins (320 in FIG. 7) in the base plate (310 in FIG. 7), andthe number of holes in each alignment hole grouping is equal to thenumber of pockets in each pocket grouping (340). The offsets of thealignment holes within each alignment hole grouping (350) are equal tothe offsets of the pockets withing each pocket grouping (340). Forexample, the offset of a second alignment hole (352) to a firstalignment hole (351) would have a first difference and a first directionequal to the first distance and first direction of the first offset of asecond pocket (342) to a first pocket (341). Similarly the offset of athird alignment hole (353) to a first alignment hole (351) would beequal to the offset of a third pocket (343) to a first pocket (341).

[0035] The block (330) is fastened to the base plate (310 in FIG. 7) byfastening means (360) in the block (330), such as unthreaded holes,through which screws pass and are threaded into one of the threadedholes in each alignment means grouping (380 in FIG. 7) in the baseplate. The threaded holes (381, 382, 383) in the alignment meansgroupings (380) in FIG. 7 are offset by distances equal to the offsetsof the pockets (341, 342, 343 in FIG. 8) but in the opposite directions,such that when the first alignment holes (351 in FIG. 8) are insertedover the alignment pins (320), the fastening means (360) in the blockare lined up to the first threaded holes (381) in the base plate.

[0036] During a package-to-package conversion, the position of the block(330) relative to the base plate (310) is changed to bring the desiredpockets (e.g. first pockets, second, pockets, etc) to the programmedlocation for picking and/or placing the semiconductor devices. Theposition of the block is changed by removing the fastening means,inserting the alignments holes from the alignment hole groupingscorresponding to the desired pockets onto the alignment pins, andattaching the fastening means to the corresponding alignment means(threaded holes) from the alignment means groupings. The presentinvention reduces set-up time because package-to-package conversion canbe achieved by repositioning the block instead of retrieving andinstalling a replacement shuttle plate. Also, costs are reduced sinceone shuttle plate according to the present invention can be used formultiple packages, instead of a different shuttle plate for eachpackage.

[0037] Referring to FIG. 9, the test arm assembly (400) of the presentinvention has a set of interchangeable vacuum leads and a set ofinterchangeable nest pieces. A vacuum lead (411) selected from the setof interchangeable vacuum leads is inserted into a through hole (460) ina test arm body (480), and retained by a test arm cap (470). The testarm cap retains the vacuum lead by a set screw on the test arm cap. Thetest arm body is attached to pick and place handler by test arm clips(490). A test arm nest piece (441) selected from the set of test armnest pieces is attached to the vacuum lead by vacuum pressure. The testarm nest piece (441) has a contact area (430) which is brought intocontact with a semiconductor device in order to perform testing on thatsemiconductor device. In one embodiment of the present invention,springs (450) are provided around the vacuum lead (410) which providesuspension to prevent damage to a semiconductor device when the contactarea is brought into contact with the semiconductor device. The test armof the present invention can be converted to a differnet package bychanging to a different vacuum lead and a different nest piece. Thisreduces set-up time compared to the prior art which requires removingone test arm, and retreiving and installing a different test arm.Inventory cost is reduced because the present invention only requiresmultiple vacuum leads and nest pieces rather than multiple test arms.Also, the present invention provides suspension, due to the spring,preventing damage to semiconductor devices when the nest piece contactsthose semiconductor devices.

[0038] While the invention has been particularly shown and describedwith reference to the preferred embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails may be made without departing from the spirit and scope of theinvention. For example, in the i/o shuttle plate, the alignment meansgroupings could be located on the block and fastening means could belocated in the base plate. Also, in the i/o shuttle plate, alignmentholes could be in the base plate, and alignment pins could be located inthe block.

What is claimed is:
 1. An input arm assembly for a pick and placehandler, comprising: (a) an input arm body having a pressure fitting, athrough hole opposite said pressure fitting, and clips for attachingsaid input arm body to a base unit for a pick and place handler; and (b)a set of interchangeable vacuum leads having different sizes; eachvacuum lead of said set of interchangeable vacuum leads having a hollowupper cylindrical portion, a hollow lower cylindrical portion, and aflange therebetween; wherein a vacuum lead with the desired size for asemiconductor device to be picked and placed is chosen from said set ofinterchangeable vacuum leads, inserted into said through hole of saidinput arm body, and retained by said pressure fitting.
 2. The input armassembly of claim 1 wherein each vacuum lead further comprises acompression spring around said upper cylindrical portion resting on saidflange; whereby, when said vacuum lead is inserted into said input armbody, said spring contacts said input arm body at its end opposite saidflange, providing suspension such that when said vacuum lead contacts asemiconductor device, said spring is compressed and the force on saidsemiconductor device is reduced.
 3. A soak buffer for a pick and placehandler, comprising an array of pocket groupings; wherein each pocketgrouping comprises the same pattern of pockets of different shapesand/or sizes to accomodate differnet semiconductor packages; wherebypackage-to package conversion can be acheived by programming an offsetinto said pick and place handler to cause the pick and place handler tomove to a different pocket in each of said pocket groupings.
 4. Aninput/output shuttle plate, comprising: (a) a block having a pluralityof pocket groupings therein, whereby each pocket grouping consists of apattern of pockets of different sizes and/or shapes having specificoffsets from each other; two or more alignment hole groupings whereineach alignment hole grouping consists of a pattern of holes having thesame offsets from each other as the corresponding pockets within saidpattern of pockets; and a plurality of attachment holes; and (b) a baseplate comprising two or more alignment pins and a plurality ofattachment means groupings wherein each attachment means groupingconsists of a pattern of attachment means having offsets from each otherwith the same distances as the offsets between corresponding pockets insaid pattern of pockets but in the opposite directions from saidpockets; whereby, when a particular alignment hole in each of saidalignment hole groupings is fitted onto said alignment pins, thecorresponding pocket in each pocket grouping is correctly located forthe pick and place handler; and said attachment holes are aligned withthe attachment means in each attachment means grouping corresponding tosaid pockets.
 5. The input/output shuttle plate of claim 4 wherein saidbase plate has two alignment pins and said block has two alignment holegroupings.
 6. The input/output shuttle plate of claim 4 wherein saidattachment means groupings consist of threaded holes, whereby said blockis fastened to said base plate by screws which are placed through anattachment hole from each attachment hole grouping and threaded into athreaded hole from each attachment means grouping.
 7. A test armassembly for a pick and place handler, comprising: (a) a test arm bodyhaving a cap thereon, a through hole opposite said cap, and test armclips for attaching said test arm assembly to said pick and placehandler; (b) a set of interchangeable vacuum leads having differentsizes; each vacuum lead of said set of interchangeable vacuum leadshaving a hollow upper cylindrical portion, a hollow lower cylindricalportion, and a flange therebetween; and (c) a set of interchangeablenest pieces each nest piece having a contact area where said nest piececontacts a corresponding semiconductor device for testing; wherein anest piece corresponding to a semiconductor device to be tested isselected from said set of nest pieces, a vacuum lead with the desiredsize for said selected nest piece is selected from said set ofinterchangeable vacuum leads, said selected vacuum lead is inserted intosaid through hole of said test arm body and retained by said cap, andsaid selected nest piece is attached to said vacuum lead by vacuumpressure.
 8. The test arm assembly of claim 7 wherein each vacuum leadfurther comprises a compression spring around said upper cylindricalportion resting on said flange; whereby, when said vacuum lead isinserted into said test arm body, said spring contacts said test armbody at its end opposite said flange, providing suspension such thatwhen said nest piece contacts a semiconductor device, said spring iscompressed and the force on said semiconductor device is reduced.
 9. Akit for package-to-package conversion of a pick and place handler,comprising: (a) an input arm assembly for a pick and place handler,comprising a set of interchangeable vacuum leads having different sizes;each vacuum lead of said set of interchangeable vacuum leads having ahollow upper cylindrical portion, a hollow lower cylindrical portion,and a flange therebetween; wherein a vacuum lead with the desired sizefor a semiconductor device to be picked and placed is chosen from saidset of interchangeable vacuum leads; (b) a soak buffer for a pick andplace handler, comprising an array of pocket groupings; wherein eachpocket grouping comprises the same pattern of pockets of differentshapes and/or sizes to accommodate different semiconductor packages;whereby package-to package conversion can be achieved by programming anoffset into said pick and place handler to cause the pick and placehandler to move to a different pocket in each of said pocket groupings;(c) an input/output shuttle plate, comprising: (i) a block having aplurality of pocket groupings therein, whereby each pocket groupingconsists of a pattern of pockets of different sizes and/or shapes havingspecific offsets from each other; two or more alignment hole groupingswherein each alignment hole grouping consists of a pattern of holeshaving the same offsets from each other as the corresponding pocketswithin said pattern of pockets; and a plurality of attachment holes; and(ii) a base plate comprising two or more alignment pins and a pluralityof attachment means groupings wherein each attachment means groupingconsists of a pattern of attachment means having offsets from each otherwith the same distances as the offsets between corresponding pockets insaid pattern of pockets but in the opposite directions from saidpockets; whereby, when a particular alignment hole in each of saidalignment hole groupings is fitted onto said alignment pins, thecorresponding pocket in each pocket grouping is correctly located forthe pick and place handler; and said attachment holes are aligned withthe attachment means in each attachment means grouping corresponding tosaid pockets; and (d) a test arm assembly for a pick and place handler,comprising: (i) a set of interchangeable vacuum leads having differentsizes; each vacuum lead of said set of interchangeable vacuum leadshaving a hollow upper cylindrical portion, a hollow lower cylindricalportion, and a flange therebetween; and (ii) a set of interchangeablenest pieces each nest piece having a contact area where said nest piececontacts a corresponding semiconductor device for testing.
 10. A methodfor package-to-package conversion of a pick and place handler,comprising the steps of: (a) removing a vacuum lead from an input armassembly having a set of interchangeable vacuum leads; (b) inserting adifferent size vacuum lead from said set of interchangeable vacuum leadsinto said input arm assembly; (c) removing a block of an input/outputshuttle plate from a base plate of said input/output shuttle plate byremoving attachment means and lifting said block off of pins on saidbase plate; said block comprising a plurality of pocket groupingstherein, whereby each pocket grouping consists of a pattern of pocketsof different sizes and/or shapes having specific offsets from eachother; said block further comprising a plurality of alignment holegroupings, whereby, when a particular alignment hole in each of saidalignment hole groupings is fitted onto said alignment pins, thecorresponding pocket in each pocket grouping is correctly located forthe pick and place handler; said base plate comprising a plurality ofattachment, whereby when a particular alignment hole in each of saidalignment hole groupings is fitted onto said alignment pins, thecorresponding attachment means in each attachment means grouping on saidbase plate is aligned with an attachment hole in said block; (d)repositioning said block on said base plate such that a selected pocketin each pocket grouping is correctly located for the pick and placehandler by fitting the alignment hole in each alignment hole groupingcorresponding to said selected pocket onto an alignment pin andfastening said block to said base plate by fastening each of saidattachment holes in said block to an attachment means in each of saidattachment means groupings corresponding to said selected pocket; saidselected pocket having a semiconductor device therein; (e) picking saidsemiconductor device with said input arm assembly, and placing saidsemiconductor device into a soak buffer having an array of pocketgroupings, wherein each pocket grouping consists of a pattern of pocketsof different shapes and/or sizes to accommodate different semiconductorpackages; whereby said pick and place handler is caused to place saidsemiconductor device into the correct pocket of each pocket grouping byprogramming an offset into the pick and place handler movement; (f)removing a nest piece and a vacuum lead from a test arm assembly havinga set of interchangeable nest pieces and a set of interchangeable vacuumleads; (g) inserting a different size vacuum lead from said set ofinterchangeable vacuum leads into said test arm assembly; and (h)attaching a different nest piece from said set of interchangeable nestpieces onto said different vacuum lead with vacuum pressure.